Autonomous Machine

Prix Fixe adds prefixes to all CSS class names in a stylesheet

Sun, 02 Jun 2013 18:40:19 +0000

I've been hacking on a mobile app using Ember.js and the CSS from Ratchet. I was trying to keep my application styles separate from those provided by the "framework", and I found myself wishing that the styles provided by Ratchet were easier to tell apart from the ones defined in my application. For example, I thought a classname like .rt-button communicated this more clearly than the basic .button.

I decided to see how hard it would be actually process a stylesheet and add prefixes to its classnames. Luckily, the SASS project had already done the difficult work of writing a CSS parser. Using their CSS importer as a starting point, I built a small script to add a prefix to the beginning of all CSS classnames in a stylesheet. This weekend, I put together Prix Fixe to make it easy for anyone to perform this kind of modification to a stylesheet.

A few caveats:

Since this tool it only operates on CSS, frameworks that ship with JavaScript will probably be broken when using prefixed styles.
Likewise, since it only modifies classnames, rules that include other types of selectors (basic elements, etc) won't be modified.

Prix Fixe works pretty well. I've been using a prefixed stylesheet on a project for a while now, and I don't plan on going back.

The source is on GitHub.

Convert string values to Ruby objects

Wed, 03 Oct 2012 19:39:43 +0000

On a project at work we've started to use environment variables to toggle features on and off in the application. We're just getting into feature toggling, and this seemed to be the best lightest-weight way to get started.

Since environment variables are strings, and some of our values will be objects of other types, we needed a way to convert these strings into Ruby objects. A preliminary search yielded many options that utilized complicated regular expressions and other gymnastics. There had to be a better way.

Enter YAML. It supports serializing the types we needed:

irb(main):001:0> require 'yaml'
=> true
irb(main):002:0> YAML.load('true')
=> true
irb(main):003:0> YAML.load('108')
=> 108
irb(main):004:0> YAML.load('just a string')
=> "just a string"

Beautiful.

Jist is a new library to publish Gists from the Ruby or the command line

Mon, 27 Aug 2012 08:20:21 +0000

A working fork of the Gist command line gem

Wed, 27 Jun 2012 13:44:26 +0000

Adds support for OAuth. To install:

$ git clone https://github.com/dr4g0nnn/gist.git
$ cd gist
$ gem build gist.gemspec
$ gem install gist-3.1.0

Hopefully at some point the official repo is brought up to date, but in the meantime, this will allow for command-line Gisting.

Troubleshooting db:push errors on Heroku

Wed, 30 May 2012 08:54:37 +0000

Here is the error I was seeing today (truncated for brevity):

$ heroku db:push --app=my-app-name --confirm=my-app-name
Loaded Taps v0.3.23
Auto-detected local database: postgres://localhost/app_development?encoding=utf8

Sending schema
Schema:        100% |==========================================| Time: 00:00:29
Sending indexes
table_1:       100% |==========================================| Time: 00:00:01
schema_migrat: 100% |==========================================| Time: 00:00:00
table_2:       100% |==========================================| Time: 00:00:00
Sending data
20 tables, 2,783 records
table_3:       0% |                                          | ETA:  --:--:--
Saving session to push_201205300813.dat..
!!! Caught Server Exception
HTTP CODE: 500
Taps Server Error: LoadError: no such file to load -- sequel/adapters/
["/app/.bundle/gems/ruby/1.9.1/gems/sequel-3.20.0/lib/sequel/core.rb:249:in `require'", ...

This was caused by my app not having a DATABASE_URL config variable set. I assumed that db:push would fail much earlier if it wasn't able to connect to a database, but this turned out to not be accurate.

The simple solution was to promote the existing database:

$ heroku pg:promote HEROKU_POSTGRESQL_COPPER --app=my-app-name

To find the name of the database to use in the previous command, use heroku config --app=my-app-name. It should have a name like HEROKU_POSTGRESQL_*_URL.

Running Ruby 1.9.3 on Heroku Cedar

Wed, 23 May 2012 07:28:11 +0000

Heroku now supports specifying a Ruby version in an application's Gemfile:

# Gemfile
ruby '1.9.3'

This requires Bundler 1.2.0, which can be installed with the --pre flag:

gem install bundler --pre

You also need to move 'bin' to the beginning of your application's PATH so the correct Ruby binary is found when starting your web processes:

heroku config:add PATH=bin:vendor/bundle/ruby/1.9.1/bin:/usr/local/bin:/usr/bin:/bin --app YOU_APP_NAME

Commit the Gemfile changes and push to Heroku, and your app should be running under Ruby 1.9.3!

Watch Railsconf 2012 presentations at ConFreaks

Wed, 16 May 2012 08:41:22 +0000

So far I've seen Yehuda Katz's and Aaron Patterson's, both of which I would recommend.

Also note that audio-only downloads are offered, which I find convenient as a frequent podcast listener.

A visual guide to some advanced CSS selectors

Wed, 16 May 2012 08:35:05 +0000

Very useful stuff. Some of the most useful are IE9+, but I doubt many will find that surprising.

Use Active Model Serializers with Mongoid

Sat, 05 May 2012 11:11:43 +0000

I'm adding some new features to Forkchop using Ember, ember-rails, and the associated active_model_serializers. The only hiccup is that I'm using Mongoid, and Active Model Serializers only hooks into Active Record when it loads. This means that Rails doesn't automatically look for the appropriate serializer when using render json: @object.

To remedy this, I added the following lines from this Gist to config/initializers/mongoid_active_model_initializers:

Mongoid::Document.send(:include, ActiveModel::SerializerSupport)
Mongoid::Criteria.delegate(:active_model_serializer, to: :to_a)

GitHub's Hidden Compare View

Wed, 18 Apr 2012 09:15:51 +0000

One of the hardest to find but most useful GitHub features.

Store Hashie::Mash objects in Mongoid Documents

Sat, 24 Mar 2012 21:50:09 +0000

I've started using Mongoid's support for abitrary field types on a project. It involves working with a lot of nested hashes that are the result of parsing JSON, and I've found wrapping a Hashie::Mash around these data structures helps keep the code interacting with them clean:

doc.data.key.another_key.and_another_key
# vs
doc.data['key']['another_key']['and_another_key']

Since Hashie::Mash objects are just a subclass of Ruby's standard Hash, they can be stored in a field that's defined as a Hash in Mongoid:

class Doc
  include Mongoid::Document
  field :data, type: Hash
end

But when these documents are loaded back out of the database, the data field will contain a standard Hash. I'd like these hashes to be Hashie::Mash instances. To accomplish this, I defined a new column type for Mongoid called Mashed:

class Mashed
  include Mongoid::Fields::Serializable

  def deserialize(object)
    Hashie::Mash.new(object)
  end

  def serialize(object)
    Hash[object]
  end
end

That's all that is required to create a new column type in Mongoid, which can be specified just like any other in your document class:

class Doc
  include Mongoid::Document
  field :data, type: Mashed
end

Now I can save and load documents with Hashie::Mash fields. This is a trivally simple example, but by replacing the implementations of deserialize and serialize above, just about any kind of object could be persisted in a Mongoid document.

RequestBin makes it easy to debug web hooks

Mon, 19 Mar 2012 21:04:29 +0000

Useful for debugging anything that makes POST requests. Just point it at RequestBin.

Tell Sprockets to precompile files other than application.js

Sat, 17 Mar 2012 21:08:56 +0000

I usually bundle all of a Rails project's JavaScript together. Occasionally, only a few pages need a large JavaScript library, and I don't want it to have to be downloaded on every page of the application. In these situations, I don't require the large library file or it's dependencies in application.js so it won't be bundled with the rest of the project's scripts. I'll add a script tag for the library to just the pages that need it, which works locally in development mode. And then inevitably I deploy and the additional files can't be found on the server because they haven't been precompiled.

It is in the docs, but I always seem to forget that for Sprockets to precompile anything other than application.js, the additional files must be specifed in config/application.rb:

config.assets.precompile += ['another_file.js']

That's all there is to it.

Briefcase is a tool to facilitate keeping dotfiles in git.

Sun, 12 Feb 2012 19:15:30 +0000

I've been using this library for my own dotfiles for the last year. I packaged it up and released it today to see if others would find it useful.

OSX GCC Installer

Mon, 06 Feb 2012 07:22:36 +0000

Install on top of Mac OS X 10.7 and Xcode 4.2.

Vim: Find and replace text across files

Fri, 03 Feb 2012 11:18:50 +0000

Performing find and replace operations across a project is something I used to do regularly in various editors, but I never took the time to learn how to do it in Vim. I finally learned how to do this today, and it turns out it's easy.

The article goes into more detail, but here are the basic commands:

:args paths/to/search/*
:argdo %s/value_to_find/replacement/ge | update

The first line sets up what files to perform the search against so it can be scoped to a certain parts of the project. %s performs the substitution, and update saves all modified files after performing the replacements.

ICO (Windows Icon) file format plugin for Photoshop

Sat, 07 Jan 2012 18:11:25 +0000

I don't know why this isn't built into Photoshop at this point, but if you need to work with ICO files, this plugin makes it painless.

Creating An Amazon IAM User Who Can Access A Single S3 Bucket

Sat, 07 Jan 2012 13:20:07 +0000

Andrew Hitchcock's tutorial on how to grant an AWS IAM user access to a single S3 bucket saved me a lot of time today. I am in the process of adding image uploading via S3 to Forkchop, and I want to have a seperate bucket and corresponding user (and therefore credentials) for each environment.

SourceTree

Sat, 07 Jan 2012 11:32:15 +0000

I started using SourceTree a week ago to as a GUI to local Git repositories. I'm comfortable using Git from the command line, but I find a GUI helpful when looking at history or selecting which parts of the current working tree I want to commit.

It's currently free, but I would pay to use it.

Understanding M17n

Wed, 04 Jan 2012 10:13:34 +0000

James Edward Gray II wrote a seven-part series of articles on character encoding in Ruby a few years ago. It is just as relevent today, and it covers just about everything one would need to know about how character encodings work in both Ruby 1.8 and 1.9.